Air curtain system for open display refrigerators

ABSTRACT

The present invention provides an open display refrigerator comprising: a refrigerated storage space, air in the refrigerated storage space being separated from air exterior to the open display refrigerator by an air curtain established by a fan which blows air towards an air outlet, air in the air curtain being recovered by an air inlet which recirculates the air from the air curtain into an air duct coupled to the air outlet, and an air guide coupled to the air outlet or air duct and extending from the air outlet such that it bypasses a portion of a void between the uppermost shelf and the air outlet, whereby the air curtain is established between an extremity of the portion of the void proximal to the air inlet and the air inlet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/GB2019/053374, entitled “Improvements To Open DisplayRefrigerators”, the entire contents of which are hereby incorporated byreference. International Patent Application No. PCT/GB2019/053374 claimspriority to G.B. Application No. 1819495.1, entitled “Improvements ToOpen Display Refrigerators”, filed on Nov. 29, 2018, and G.B.Application No. 1906935.0, entitled “Process for Optimising the Positionof Refrigerator Air Guides in Order to Achieve Increased EnergyEfficiency of the Refrigerator”, filed on May 16, 2019.

FIELD

The invention relates to open display refrigerators, and to coolingunits (refrigerators or freezers) which have doors comprisingtransparent windows. The invention also relates to methods of modifyingsuch open display refrigerators and cooling units.

BACKGROUND

Open display refrigerators are commonly used in retail environments,such as supermarkets, to store and display products, such as meat anddairy products, which must be kept at lower than ambient temperatures.The open front of such a refrigerator makes it easy for customers toview the products being displayed and to retrieve products they wish topurchase from the refrigerator.

This type of refrigerator has an air curtain, which is established byblowing cold air across the front of the refrigerator. The air curtainissues from an air outlet at the top of the refrigerator towards an airinlet at the bottom of the refrigerator. The air inlet recovers air fromthe air curtain and recirculates it to the air outlet via a cooling heatexchanger and fan.

Generally, it is intended that the air curtain follows a broadly linearpath from the air outlet to the air inlet thereby preventing cold air inthe refrigerator from mixing with warm air exterior to the refrigerator.However, some configurations include a sizeable void between theuppermost shelf and the air outlet into which air from the air curtaintends to rush. This causes the air curtain to deviate from the intendedgenerally linear path and move towards the interior of the refrigerator.Where the air curtain is drawn towards the interior of the refrigerator,the air flow of the air curtain is broken up and becomes more turbulentwhen compared to an air curtain that follows a generally linear path.The breaking up of the air curtain and the turbulence causes the aircurtain to be less efficient at preventing cold air in the refrigeratorfrom mixing with warm air exterior to the refrigerator and hence causesthe interior of the refrigerator to be warmer than a refrigerator with agenerally linear air curtain.

A further inefficiency arises where warm air (i.e. air that is warmerthan the refrigerated interior) proximate the top exterior surface ofthe refrigerator is drawn around the front uppermost edge of therefrigerator by the flowing air of the air curtain and impinges on theair curtain as the air curtain leaves the air outlet. This causes warmair to become entrained in the air curtain and also breaks the smoothflow of the air curtain. Again, this causes the interior of therefrigerator to be warmer than a refrigerator with a generally linearair curtain.

For refrigerators with an uppermost shelf that is installed at an angleto the normal, where an edge of the shelf distal to the rear of therefrigerator is lower than an edge of the shelf proximate the rear ofthe refrigerator, the void between the angled uppermost shelf and theair outlet is larger than with a refrigerator comprising a flatuppermost shelf that is not installed at an angle. Hence the issue ofthe air curtain deviating from a generally linear path when an angledshelf is used is even more pronounced. Generally these angled shelves donot have any additional air guides or aerofoils for guiding the aircurtain, because they can be cumbersome to fit to angled shelves andgenerally retailers are unwilling to fit them to angled shelves. Assuch, it is important that the air curtain follows a generally linearpath because the path of the air curtain is not purposefully altered ormaintained between the point at which the air curtain is established andthe point at which the air curtain enters the air inlet.

SUMMARY

In accordance with a first aspect of the invention, there is provided anopen display refrigerator comprising: a refrigerated storage space, airin the refrigerated storage space being separated from air exterior tothe open display refrigerator by an air curtain established by a fanwhich blows air towards an air outlet, air in the air curtain beingrecovered by an air inlet which recirculates the air from the aircurtain into an air duct coupled to the air outlet, and an air guidecoupled to the air outlet or air duct and extending from the air outletsuch that it bypasses a portion of a void between the uppermost shelfand the air outlet, whereby the air curtain is established between anextremity of the portion of the void proximal to the air inlet and theair inlet.

In this aspect, by “interface between the air curtain and the airexterior to the refrigerator” it is meant that the boundary where theair at a distal edge of the air curtain (which may be cooled by a heatexchanger of the refrigerator, and is blown through the air outlet bythe fan), i.e. the edge of the air curtain which is furthest from a rearinterior wall of the refrigerator, meets the air exterior to the opendisplay refrigerator.

In accordance with a second aspect of the invention, there is provided acooling unit comprising an interior space and a door; wherein the doorcomprises a transparent window and separates the interior space from airexternal to the cooling unit; and wherein the interior space comprises(i) a refrigerated storage space and (ii) an access space; wherein airin the refrigerated storage space is separated from air in the accessspace by an air curtain established by a fan which blows air towards anair outlet, air in the air curtain being recovered by an air inlet whichrecirculates the air from the air curtain into an air duct coupled tothe air outlet, and an air guide coupled to the air outlet or air ductand extending from the air outlet such that it bypasses a portion of avoid between the uppermost shelf and the air outlet, whereby the aircurtain is established between an extremity of the portion of the voidproximal to the air inlet and the air inlet.

In this aspect, by “interface between the air curtain and the accessspace” it is meant the boundary where the air at a distal edge of theair curtain (which may be cooled by a heat exchanger of the coolingunit, and is blown through the air outlet by the fan), i.e. the edge ofthe air curtain which is further from a rear interior wall of thecooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features describedin the following paragraphs may relate to open display refrigerators orcooling units according to any of the first or second aspects of theinvention.

As the air guide bypasses a portion of the void between the uppermostshelf and the air outlet, the effect of the void on the path of the aircurtain is reduced and hence the air curtain follows a more linear path.Further, as the air guide extends from the air outlet, the air guidehelps prevent warm air proximate the top exterior surface of therefrigerator from being drawn around the front uppermost edge of therefrigerator and impinging on the air curtain as the air curtain leavesthe air outlet, because the air guide forms a barrier that extends fromthe air outlet.

An advantage of using the air guide is that any honeycomb structure thatis present in the air outlet may be removed. This reduces the resistanceto the air flowing through the air outlet and enhances the performanceof the air curtain, as the velocity of the air curtain is increased. Anincrease in velocity makes the air curtain more resistant to being drawninto the void between the uppermost shelf and the air outlet as well asbeing more resistant to breaking up when warm air impinges on the aircurtain.

In some embodiments, an uppermost shelf is at an angle to thehorizontal, such that an edge of the shelf that is proximate a rear wallof the refrigerated storage space is higher than an edge of the shelfthat is distal to the rear wall of the refrigerated storage space.

In some embodiments, the air guide comprises an air guide inlet throughwhich the air enters and an air guide outlet at which the air curtain isestablished, and wherein the air guide outlet is offset relative to theair guide inlet. The air guide outlet may be offset away from, or beoffset distal to, the rear wall of the refrigerated storage space, withrespect to the air guide inlet. The body of the air guide may have achicane shape or an “S” shape. The chicane shape or the “S” shape may bemade up of a curve in a first direction and a curve in a seconddirection. Alternatively, the body of the air guide may comprise asingle curve. In some embodiments a part of the air guide may extendinto the duct. In particular, an outermost side or a distal side (withrespect to the refrigerated interior) of the air guide may extend intothe duct. A technical advantage of all of these configurations is thatthe air guide can be better customised to work with the air flowcharacteristics of different fridges.

In some embodiments, the air guide comprises an air guide inlet throughwhich the air enters and an air guide outlet at which the air curtain isestablished, and wherein the air guide outlet is aligned with the airguide inlet.

In some embodiments, a cross sectional area of the air guide inlet islarger than a cross sectional area of an air guide outlet, therebycausing the velocity of the air to increase as it passes through the airguide. An advantage of this arrangement is that the increase in airspeed makes the air curtain more resistant to being drawn into the voidand also helps to prevent the warm air drawn from the volume proximatethe top exterior surface of the refrigerator from disrupting the path ofthe air curtain and being entrained into the air curtain.

In some embodiments, a cross sectional area of the air guide inlet issmaller than a cross sectional area of an air guide outlet. A technicaladvantage of such an air guide is that computer modelling shows thatthis improves the air flow of the air curtain in some types ofrefrigerator.

In some embodiments, a cross sectional area of the air guide inlet isthe same, or is substantially the same, as a cross sectional area of anair guide outlet.

In some embodiments, there is at least one additional air outlet in arear interior wall of the refrigerator or cooling unit.

In some embodiments, the refrigerator or cooling unit includes ahoneycomb structure positioned in the air outlet, the honeycombstructure being a cellular matrix of channels which extend in alongitudinal direction parallel to the air flow.

In some embodiments, the refrigerator or cooling unit include ahoneycomb structure positioned in the air guide outlet, the honeycombstructure being a cellular matrix of channels which extend in alongitudinal direction parallel to the air flow of the air curtain.

In some embodiments, the cooling unit is a refrigerator.

In some embodiments, the cooling unit is a freezer.

In accordance with a third aspect of the invention, there is provided amethod of selecting an air guide from a plurality of air guides for usewith an open display refrigerator, wherein the open display refrigeratorcomprises a refrigerated storage space, air in the refrigerated storagespace being separated from air exterior to the open display refrigeratorby an air curtain established by a fan which blows air towards an airoutlet, air in the air curtain being recovered by an air inlet whichrecirculates the air from the air curtain into an air duct coupled tothe air outlet and wherein the method comprises: a) providing an arrayof temperature sensors within an interior of the open displayrefrigerator; b) measuring an initial temperature difference between thewarmest temperature recorded by the array of temperature sensors and thecoldest temperature recorded by the array of temperature sensors; c)coupling one or more air guides to the air outlet or air duct such thatthe or each air guide extends from the air outlet and bypasses a portionof a void between the uppermost shelf and the air outlet, whereby theair curtain is established between an extremity of the portion of thevoid proximal to the air inlet and the air inlet; d) measuring arespective final temperature difference associated with the or each airguide, the or each final temperature difference being the temperaturedifference between the warmest temperature recorded by the array oftemperature sensors and the coldest temperature recorded by the array oftemperature sensors after the associated air guide has been coupled tothe air outlet or air duct; e) selecting an air guide from the one ormore air guides, whereby the difference between the initial temperaturedifference and the final temperature difference associated with theselected air guide is at least a threshold temperature difference, orselecting the air guide from the one or more air guides for which thedifference between the initial temperature difference and the associatedfinal temperature difference is greatest.

In this aspect, by “interface between the air curtain and the airexterior to the refrigerator” it is meant that the boundary where theair at a distal edge of the air curtain (which may be cooled by a heatexchanger of the refrigerator, and is blown through the air outlet bythe fan), i.e. the edge of the air curtain which is furthest from a rearinterior wall of the refrigerator, meets the air exterior to the opendisplay refrigerator.

In accordance with a fourth aspect of the invention, there is provided amethod of selecting an air guide from a plurality of air guides for usewith a cooling unit, wherein the cooling unit comprises an interiorspace and a door; wherein the door comprises a transparent window andseparates the interior space from air external to the cooling unit;wherein the interior space comprises (i) a refrigerated storage spaceand (ii) an access space; wherein air in the refrigerated storage spaceis separated from air in the access space by an air curtain establishedby a fan which blows air towards an air outlet for recovery by acorresponding air inlet which recirculates air from the air curtain intoan air duct coupled to the air outlet and wherein the method comprises:a) providing an array of temperature sensors within an interior of thecooling unit; b) measuring an initial temperature difference between thewarmest temperature recorded by the array of temperature sensors and thecoldest temperature recorded by the array of temperature sensors; c)coupling one or more air guides to the air outlet or air duct such thatthe or each air guide extends from the air outlet and bypasses a portionof a void between the uppermost shelf and the air outlet, whereby theair curtain is established between an extremity of the portion of thevoid proximal to the air inlet and the air inlet; d) measuring arespective final temperature difference associated with the or each airguide, the or each final temperature difference being the temperaturedifference between the warmest temperature recorded by the array oftemperature sensors and the coldest temperature recorded by the array oftemperature sensors after the associated air guide has been coupled tothe air outlet or air duct; e) selecting an air guide from the one ormore air guides, whereby the difference between the initial temperaturedifference and the final temperature difference associated with theselected air guide is at least a threshold temperature difference, orselecting the air guide from the one or more air guides for which thedifference between the initial temperature difference and the associatedfinal temperature difference is greatest.

In this aspect, by “interface between the air curtain and the accessspace” it is meant the boundary where the air at a distal edge of theair curtain (which may be cooled by a heat exchanger of the coolingunit, and is blown through the air outlet by the fan), i.e. the edge ofthe air curtain which is furthers from a rear interior wall of thecooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features describedin the following paragraphs may relate to open display refrigerators orcooling units according to any of the third or fourth aspects of theinvention.

The temperature may be measured by placing numerous jelly-bricks(examples of jelly-bricks known in the art are Tylose packs or M-Packs)on the shelves of the refrigerator. Each jelly-brick has its owntemperature probe, each of which makes up the array of temperatureprobes, so that the temperature at different points in the fridge can betracked. As the location of the warmest jelly-brick and the location ofthe coolest jelly-brick may change with the addition of the air guideand/or adjustments made to the air guide, the difference between thewarmest jelly-brick and the coolest jelly brick is measured.

The pre-determined threshold may be any meaningful temperaturedifference and will depend on the size and the geometry of therefrigerator. Meaningful temperature differences may be any number, atincrements of 0.1° C., in the range of 0.1° C.-10° C. In practice, it islikely that values that are multiples of 0.5° C. and 1° C. would bechosen. The temperature difference may be optimised by selecting an airguide with dimensions (including length, diameter, change incross-section, amount of offset) that gives the biggest reduction intemperature difference.

In some embodiments, the array of temperature sensors are providedwithin the refrigerated storage space.

In some embodiments, a temperature sensor of the array of temperaturesensors is provided proximate the air inlet.

In some embodiments, the air guide, and hence the path of the aircurtain, is adjusted such that the temperature difference is furtherreduced. Examples of adjusting the air guide include positioning wherethe air guide is coupled to the air outlet or duct, adjusting anadjustable part joint on the air guide, such that the air guide inletremains static and the air guide outlet is moveable or adjusting aplastic part of the air guide, such that a cross-section of the airguide is reduced or increased.

In accordance with a fifth aspect of the invention, there is provided akit for retrofitting an air guide to an open display refrigerator,wherein the open display refrigerator comprises a refrigerated storagespace, air in the refrigerated storage space being separated from airexterior to the open display refrigerator by an air curtain establishedby a fan which blows air towards an air outlet, air in the air curtainbeing recovered by an air inlet which recirculates the air from the aircurtain into an air duct coupled to the air outlet and wherein the kitcomprises: an air guide for coupling to the air outlet or air duct; andan attachment for fastening the air guide to the air outlet or air duct.

In this aspect, by “interface between the air curtain and the airexterior to the refrigerator” it is meant that the boundary where theair at a distal edge of the air curtain (which may be cooled by a heatexchanger of the refrigerator, and is blown through the air outlet bythe fan), i.e. the edge of the air curtain which is furthest from a rearinterior wall of the refrigerator, meets the air exterior to the opendisplay refrigerator.

In accordance with a sixth aspect of the invention, there is provided akit for retrofitting an air guide to a cooling unit, wherein the coolingunit comprises an interior space and a door; wherein the door comprisesa transparent window and separates the interior space from air externalto the cooling unit; and wherein the interior space comprises (i) arefrigerated storage space and (ii) an access space; wherein air in therefrigerated storage space is separated from air in the access space byan air curtain established by a fan which blows air towards an airoutlet, air in the air curtain being recovered by an air inlet whichrecirculates the air from the air curtain into an air duct coupled tothe air outlet, and wherein the kit comprises: an air guide for couplingto the air outlet or air duct; and an attachment for fastening the airguide to the air outlet or air duct.

In this aspect, by “interface between the air curtain and the accessspace” it is meant the boundary where the air at a distal edge of theair curtain (which may be cooled by a heat exchanger of the coolingunit, and is blown through the air outlet by the fan), i.e. the edge ofthe air curtain which is furthers from a rear interior wall of thecooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features describedin the following paragraphs may relate to open display refrigerators orcooling units according to any of the fifth or sixth aspects of theinvention.

In some embodiments, the attachment comprises clips integral to the airguide, which are received in the open air refrigerator or the coolingunit proximate the air outlet or the air duct.

In some embodiments, the attachment comprises screws or rivets.

In some embodiments, the attachment comprises mastic or adhesive.

In accordance with a seventh aspect of the invention, there is provideda method of modifying an open display refrigerator, wherein the opendisplay refrigerator comprises a refrigerated storage space, air in therefrigerated storage space being separated from air exterior to the opendisplay refrigerator by an air curtain established by a fan which blowsair towards an air outlet, air in the air curtain being recovered by anair inlet which recirculates the air from the air curtain into an airduct coupled to the air outlet, the method comprising: coupling an airguide to the air outlet or air duct, wherein the air guide has an airguiding surface which causes the air to bypass a portion of a voidbetween the uppermost shelf and the air outlet or air duct prior to itleaving an air guide outlet, such that an air curtain is establishedbetween an extremity of the portion of the void proximal to the airinlet and the air inlet.

In this aspect, by “interface between the air curtain and the airexterior to the refrigerator” it is meant that the boundary where theair at a distal edge of the air curtain (which may be cooled by a heatexchanger of the refrigerator, and is blown through the air outlet bythe fan), i.e. the edge of the air curtain which is furthest from a rearinterior wall of the refrigerator, meets the air exterior to the opendisplay refrigerator.

In accordance with an eighth aspect of the invention, there is provideda method of modifying a cooling unit, wherein the cooling unit comprisesan interior space and a door; wherein the door comprises a transparentwindow and separates the interior space from air external to the coolingunit; wherein the interior space comprises (i) a refrigerated storagespace and (ii) an access space; wherein air in the refrigerated storagespace is separated from air in the access space by an air curtainestablished by a fan which blows air towards an air outlet for recoveryby a corresponding air inlet which recirculates air from the air curtaininto an air duct coupled to the air outlet and wherein the methodcomprises: coupling an air guide to the air outlet or air duct, whereinthe air guide has an air guiding surface which causes the air to bypassa portion of a void between the uppermost shelf and the air outlet orair duct prior to it leaving an air guide outlet, such that an aircurtain is established between an extremity of the portion of the voidproximal to the air inlet and the air inlet.

In this aspect, by “interface between the air curtain and the accessspace” it is meant the boundary where the air at a distal edge of theair curtain (which may be cooled by a heat exchanger of the coolingunit, and is blown through the air outlet by the fan), i.e. the edge ofthe air curtain which is furthers from a rear interior wall of thecooling unit, meets the access space.

Unless specifically mentioned otherwise, the optional features describedin the following paragraphs may relate to open display refrigerators orcooling units according to any of the seventh or eighth aspects of theinvention.

In some embodiments, the air guide is coupled to the air outlet or airduct by clips integral to the air guide, which are received in the openair refrigerator or the cooling unit proximate the air outlet or the airduct.

In some embodiments, the air guide is coupled to the air outlet or airduct with screws or rivets.

In some embodiments, the air guide is coupled to the air outlet or airduct with mastic or adhesive.

In some embodiments, the air guide comprises an air guide inlet throughwhich the air enters and an air guide outlet at which the air curtain isestablished, and wherein the air guide outlet is offset relative to theair guide inlet. The air guide outlet may be offset away from, or beoffset distal to, the rear wall of the refrigerated storage space, withrespect to the air guide inlet. The body of the air guide may have achicane shape or an “S” shape. The chicane shape or the “S” shape may bemade up of a curve in a first direction and a curve in a seconddirection. Alternatively, the body of the air guide may comprise asingle curve. In some embodiments a part of the air guide may extendinto the duct. In particular, an outermost side or a distal side (withrespect to the refrigerated interior) of the air guide may extend intothe duct. A technical advantage of all of these configurations is thatthe air guide can be better customised to work with the air flowcharacteristics of different fridges.

In some embodiments, the air guide comprises an air guide inlet throughwhich the air enters and an air guide outlet at which the air curtain isestablished, and wherein the air guide outlet is aligned with the airguide inlet.

In some embodiments, a cross sectional area of the air guide inlet islarger than a cross sectional area of an air guide outlet, therebycausing the velocity of the air to increase as it passes through the airguide.

In some embodiments, a cross sectional area of the air guide inlet issmaller than a cross sectional area of an air guide outlet.

In some embodiments, a cross sectional area of the air guide inlet isthe same, or is substantially the same, as a cross sectional area of anair guide outlet.

In some embodiments, the method further comprises removing a honeycombstructure from the air guide outlet or air duct, the honeycomb structurebeing a cellular matrix of channels which extend in a longitudinaldirection parallel to the air flow of the air curtain.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the invention will now be described with reference to theaccompanying drawings, in which:

FIG. 1 shows an open display refrigerator in which the shelves areangled and a void is formed between the uppermost shelf and the airoutlet.

FIG. 2 shows the difference between the intended line of the air curtainof the open display refrigerator of FIG. 1 and the actual path of theair curtain due to the void between the uppermost shelf and the airoutlet and the warm air which is drawn from the top of the refrigerator.

FIG. 3 shows an open air refrigerator with an air guide coupled to theair outlet.

FIG. 4 shows method steps for selecting an air guide from a plurality ofair guides for use with a refrigerator.

DETAILED DESCRIPTION

FIG. 1 shows a cross-section through an open display refrigerator 1. Therefrigerator has a storage space 2 that is maintained at a lower thanambient temperature. Within the storage space 2, there are four angledstorages shelves 3 a-3 d. Different embodiments may have one, two,three, five or any number of storage shelves which may be flat, may beat an angle or may be a mix of angled and flat shelves. A typical anglefor the angled storage shelves is 20°, however shelves at other anglesmay be used, as long as the product being refrigerated does not slideoff of the shelves. As can be seen, a void 6 is formed between theuppermost storage shelf 3 a and the air outlet 4. The refrigerator 1establishes an air curtain (not shown) by a fan (not shown) which blowscold air towards an air outlet 4, out of the air outlet 4 and towards anair inlet 5. Air inlet 5 recovers air from the air curtain and a fan(not shown) within the refrigerator 1 recirculates the air to the airoutlet 4. A cooling unit or heat exchanger (not shown) within therefrigerator 1 maintains the recirculated air (and hence the air blownthrough the air outlet 4 to form the air curtain) at a desiredtemperature. The desired temperature is chosen to be lower than ambientand acts to prevent cold air in the storage space 2 from mixing withwarm air exterior to the refrigerator.

In FIG. 2, the impact of the void 6 and the impact of warm air beingdrawn around the top of the refrigerator on the intended path of the aircurtain is shown. The path of the warm air is indicated by the curvedarrow 7. The intended path of the air curtain is indicated by the dottedline 8 and the deflected path of the air curtain is indicated by thedashed line 9. As can be seen, the air curtain moves towards theinterior of the refrigerator in an unintended manner, which leads toincreased temperatures at the bottom of the refrigerated storage space2, when compared to a refrigerator that has a generally linear aircurtain.

FIG. 3 shows a solution as provided by the present invention to theproblem associated with the void between the uppermost shelf and the airoutlet and also the problem associated with warm air being drawn fromthe top of the refrigerator and impinging on the air curtain. Across-section through the open display refrigerator 1 is shown. As inFIGS. 1 and 2, the refrigerator 1 comprises a refrigerated storage space2. Air in the refrigerated storage space 2 is separated from airexterior to the open display refrigerator 1 by an air curtain, indicatedby the dashed line 10, established by a fan (not shown) which blows airtowards an air outlet 4 and through an air guide 12 coupled to the airoutlet 4 towards a corresponding air inlet, which recovers air from theair curtain for recirculation through an air duct 11 to the air guide12. The air guide extends from the air outlet 4 such that it bypasses aportion of the void 6 formed between the uppermost shelf 3 a and the airoutlet 4. As shown, the air guide outlet may be offset away from, or beoffset distal to, the rear wall of the refrigerated storage space withrespect to the air guide inlet. This results in an air curtain thatfollows a more linear path, as the effect of the void on the air curtainis reduced. This is realised because the air guide bypasses a portion ofthe void between the uppermost shelf and the air outlet and prevents airfrom rushing into the void, hence the effect of the void on the path ofthe air curtain is reduced and the air curtain follows a more linearpath. Further, as the air guide extends from the air outlet, the airguide helps prevent warm air proximate the top exterior surface of therefrigerator from being drawn around the front uppermost edge of therefrigerator and impinging on the air curtain as the air curtain leavesthe air outlet, because the air guide forms a barrier that extends fromthe air outlet and the air curtain is no longer proximal to the warmair. An advantage of the air guide only bypassing a portion of the voidis that the air curtain follows the intended path more closely and userscan easily see and access items on the top angled shelf.

Although the air guide 12 shown in FIG. 3 shows an air guide wherein theair guide outlet is offset away from, or is offset distal to, the rearwall of the refrigerated storage space with respect to the air guideinlet, other air guides may be used to achieve the same technicaleffect. For example, an air guide comprising an air guide inlet throughwhich the air enters and an air guide outlet at which the air curtain isestablished, wherein the air guide outlet is aligned, or issubstantially aligned, with the air guide inlet, may be used. In otherembodiments, the body of the air guide may have a chicane shape or an“S” shape. The chicane shape or the “S” shape may be made up of a curvein a first direction and a curve in a second direction. Alternatively,the body of the air guide may comprise a single curve. In someembodiments a part of the air guide may extend into the duct. Inparticular, an outermost side or a distal side (with respect to therefrigerated interior) of the air guide may extend into the duct. Atechnical advantage of all of these configurations is that the air guidecan be better customised to work with the air flow characteristics ofdifferent fridges.

A cross sectional area of the air guide inlet of the air guide 12 shownin FIG. 3 is substantially the same as a cross sectional area of an airguide outlet. Air guides with different cross-sectional areas may alsobe used, for example an air guide wherein a cross sectional area of theair guide inlet is larger than a cross sectional area of an air guideoutlet may be used. Alternatively, an air guide wherein a crosssectional area of the air guide inlet is smaller than a cross sectionalarea of an air guide outlet may also be used.

The air guide 12 may be coupled to the refrigerator using any of screws,rivets, mastic, adhesive or any other way of attachment known to theperson skilled in the art.

FIG. 4 shows a method of selecting an air guide from a plurality of airguides for use with an open display refrigerator, wherein the opendisplay refrigerator comprises a refrigerated storage space, air in therefrigerated storage space being separated from air exterior to the opendisplay refrigerator by an air curtain established by a fan which blowsair towards an air outlet, air in the air curtain being recovered by anair inlet which recirculates the air from the air curtain into an airduct coupled to the air outlet and wherein the method comprises:providing an array of temperature sensors within an interior of the opendisplay refrigerator 100; measuring an initial temperature differencebetween the warmest temperature recorded by the array of temperaturesensors and the coldest temperature recorded by the array of temperaturesensors 101; coupling one or more air guides to the air outlet or airduct such that the or each air guide extends from the air outlet andbypasses a portion of a void between the uppermost shelf and the airoutlet, whereby the air curtain is established between an extremity ofthe portion of the void proximal to the air inlet and the air inlet 102;measuring a respective final temperature difference associated with theor each air guide, the or each final temperature difference being thetemperature difference between the warmest temperature recorded by thearray of temperature sensors and the coldest temperature recorded by thearray of temperature sensors after the associated air guide has beencoupled to the air outlet or air duct 103; selecting an air guide fromthe one or more air guides, whereby the difference between the initialtemperature difference and the final temperature difference associatedwith the selected air guide is at least a threshold temperaturedifference, or selecting the air guide from the one or more air guidesfor which the difference between the initial temperature difference andthe associated final temperature difference is greatest 104.

In some embodiments, the array of temperature sensors are providedwithin the refrigerated storage space. In some embodiments, atemperature sensor of the array of temperature sensors is providedproximate the air inlet. In some embodiments the air guide, and hencethe path of the air curtain, is adjusted such that the temperaturedifference is further reduced.

In some embodiments, the method may include steps that comprisemeasuring the temperature by placing numerous jelly-bricks (examples ofjelly-bricks known in the art are Tylose packs or M-Packs) on theshelves of the refrigerator, wherein each jelly-brick has its owntemperature probe, each of which makes up the array of temperatureprobes, so that the temperature at different points in the fridge can betracked. As the location of the warmest jelly-brick and the location ofthe coolest jelly-brick may change with the addition of the air guideand/or adjustments made to the air guide, the difference between thewarmest jelly-brick and the coolest jelly brick may be measured asopposed to measuring the same jelly-bricks before and after adding oradjusting the air guide.

1. An apparatus, comprising: a housing defining a refrigerated storagespace; a shelf disposed within the refrigerated storage area; an airoutlet; a fan configured to blows air towards the air outlet to form anair curtain that separates the refrigerated storage area from anexterior of the housing; an air inlet; an air duct that fluidicallycouples the air inlet to the air outlet such that air from the aircurtain can be recirculated through the air outlet; and an air guideprojecting from the air outlet, a length of the air guide configured tocause the air curtain to bypass at least a portion of a void between theshelf and the air outlet.
 2. (canceled)
 3. The apparatus of claim 1,wherein the shelf is an uppermost shelf that is at an angle to thehorizontal such that a rear edge of the shelf is higher than a frontedge of the shelf.
 4. The apparatus of claim 1, wherein the air guidecomprises an air guide inlet coupled to the air outlet and an air guideoutlet at which the air curtain is established, the air guide inletseparated by the air guide outlet by the length of the air guide. 5.(canceled)
 6. The apparatus of claim 4, wherein a cross sectional areaof the air guide inlet is larger than a cross sectional area of an airguide outlet such that a velocity of air increases as it passes throughthe air guide.
 7. The apparatus of claim 4, wherein a cross sectionalarea of the air guide inlet is smaller than a cross sectional area of anair guide outlet. 8.-9. (canceled)
 10. The apparatus of claim 1, furthercomprising a honeycomb structure positioned in the air outlet, thehoneycomb structure being a cellular matrix of channels which extend ina longitudinal direction parallel to the air flow.
 11. The apparatus ofclaim 4, further comprising a honeycomb structure positioned in the airguide outlet, the honeycomb structure being a cellular matrix ofchannels which extend in a longitudinal direction parallel to the airflow of the air curtain. 12.-13. (canceled)
 14. A method, comprising:measuring an initial temperature difference between a warmest initialtemperature sensed by an array of temperature sensors disposed within arefrigerated housing and a coldest initial temperature sensed by thearray of temperature sensors, the initial temperature differencemeasured with no air guide coupled to an air outlet that is configuredto produce air for an air curtain that separates an interior of therefrigerated housing from an exterior of the refrigerated housing;coupling a first air guide to the air outlet such that a length of thefirst air guide is causes the air curtain to bypass a portion of a voidbetween an uppermost shelf within the refrigerated housing and the airoutlet; measuring a first temperature difference between a warmest firsttemperature sensed by the array of temperature sensors when the firstair guide is coupled to the air outlet and a coldest first temperaturesensed by the array of temperature sensors when the first air guide iscoupled to the air guide outlet; removing the first air guide from theair outlet; coupling a second air guide to the air outlet after removingthe first air guide from the air outlet, the second air guide beingdifferent from the first air guide, the second air guide coupled to theair outlet such that a length of the second air guide causes the aircurtain to bypass a portion of the void between the uppermost shelf andthe air outlet; measuring a second temperature difference between awarmest second temperature sensed by the array of temperature sensorswhen the second air guide is coupled to the air outlet and a coldestsecond temperature sensed by the array of temperature sensors when thesecond air guide is coupled to the air outlet; measuring a secondtemperature difference between a warmest second temperature sensed bythe array of temperature sensors when the second air guide is coupled tothe outlet and a second coldest temperature sensed by the array oftemperature sensors when the second air guide is coupled to the airoutlet; and selecting the second air guide based on at least one of adifference between the initial temperature difference and the secondtemperature difference exceeding a threshold, or the second temperaturedifference being greater than the first temperature difference. 15.-17.(canceled)
 18. The method of claim 14, further comprising adjusting thesecond air guide such that the second temperature difference is furtherreduced. 19.-23. (canceled)
 24. A method, comprising: coupling an airguide to an air outlet that is configured to produce air for an aircurtain that separates an interior of a refrigerated housing from anexterior of a refrigerated housing, the air guide having an air guidingsurface configured to cause the air curtain to bypass a portion of avoid between an uppermost shelf in the refrigerated housing and the airoutlet; and adjusting the air guide to reduce a difference between awarmest temperature measured by at least one temperature sensor disposedwithin the interior of the refrigerated housing and a coldesttemperature measured by the at least one temperature sensor. 25.(canceled)
 26. The method of claim 24, wherein the air guide is coupledto the air outlet by clips integral to the air guide.
 27. The method ofclaim 24, wherein the air guide is coupled to the air outlet with atleast one of screws or rivets.
 28. The method of claim 24, wherein theair guide is coupled to the air outlet with at least one of mastic oradhesive.
 29. The method of claim 24, wherein the air guide comprises anair guide inlet through which air enters and an air guide outlet atwhich the air curtain is established, and wherein the air guide outletis offset relative to the air guide inlet.
 30. The method of claim 24,wherein the air guide comprises an air guide inlet through which the airenters and an air guide outlet at which the air curtain is established,and wherein the air guide outlet is aligned with the air guide inlet.31. The method of claim 24, wherein a cross sectional area of an airguide inlet is larger than a cross sectional area of an air guide outletsuch that a velocity of air increases as it passes through the airguide.
 32. The method of claim 24, wherein a cross sectional area of anair guide inlet is smaller than a cross sectional area of an air guideoutlet.
 33. The method of claim 24, wherein a cross sectional area ofair guide inlet is the same, or is substantially the same, as a crosssectional area of an air guide outlet.
 34. The method of claim 24,further comprising removing a honeycomb structure from at least one ofthe air guide outlet or air duct, the honeycomb structure being acellular matrix of channels which extend in a longitudinal directionparallel to the air flow of the air curtain.